The present invention relates to a motor drive control apparatus in a vehicle, particularly to a motor drive control apparatus capable of ensuring firm starting performance of an engine, capable of promoting durability of a starter, capable of simplifying control of a motor and capable of increasing reliability of the control of the motor.
As a kind of vehicles, there is a so-to-speak hybrid vehicle mounted with an internal combustion engine and an electric motor as power sources for propelling the vehicle. This kind of vehicle achieves requested functions (reduced fuel cost, reduced poisonous component values of emission, adequate power function) at higher levels by providing engine control means and motor control means for controlling operating states of the engine and the motor, respectively detecting the operating states of the engine and the motor, exchanging detected operational data of the engine and the motor between the engine control means and the motor control means and controlling the operating states of the engine and the motor in relation to each other.
There are disclosed such a vehicle motor control apparatus in Japanese Utility Model Laid-Open No. 61432/1993 and Japanese Utility Model Laid-Open No. 72544/1993.
According to the vehicle motor control apparatus disclosed in Japanese Utility Model Laid-Open No. 61432/1993, in a hybrid engine in which a rotating machine having functions of power generation and electrical drive is connected in parallel with a drive system of an internal combustion engine. There are provided power generation control means and electrical drive control means for controlling the rotating machine. The electrical drive control means is provided with electrical drive mode control means for setting a drive assist amount by a predetermined time period in the case of low temperatures and engine load setting means for setting power of the engine for supplementing power deficient in the drive assist amount.
According to the vehicle motor control apparatus disclosed in Japanese Utility Model Laid-Open No. 72544/1993, an engine of a mobile work vehicle is integrated with an induction machine provided with a motor function and a power generation function. The vehicle is further provided with control means for supplying torque from the induction machine to the engine when output torque of the engine is large, and generating electricity by the induction machine with the extra torque and charging electricity to a battery when the output torque of the engine is small.
Further, there is a vehicle motor control apparatus for controlling the drive of a motor in accordance with driving a starter connected to an engine. There are disclosed vehicle motor control apparatus of this kind in Japanese Patent Laid-Open No. 136508/1998 and Japanese Patent Laid-Open No. 169535/1998.
According to the vehicle motor control apparatus disclosed in Japanese Patent Laid-Open No. 136508/1998, in a hybrid vehicle provided with an engine and an electrically-driven motor as power sources and provided with a starter for starting the engine, normally, the engine is cranked to start by the electrically-driven motor. When the engine cannot be started by the electrically-driven motor, the engine is started by the starter. Further, the engine is cranked to start by the starter and the cranking operation is assisted by the electrically-driven motor as required.
According to the vehicle motor control apparatus disclosed in Japanese Patent Laid-Open No. 169535/1998, a cranking time period or a rotational number of stopping to crank an engine and the number of times of restarting the engine are determined based on water temperature of the engine, starting conditions are determined in accordance with the state of the engine and a starter is controlled in compliance with the starting conditions.
Meanwhile, according to the conventional motor control apparatus provided with the starter connected to the engine of a so-to-speak hybrid vehicle for controlling to drive the motor in accordance with driving the starter, as disclosed in Japanese Patent Laid-Open No. 136508/1998, mentioned above, the engine is cranked to start by the starter and the cranking operation is assisted by the electrically driven motor as required.
However, according to the conventional motor control apparatus, in cranking to start the engine by the starter, the electrically-driven motor is driven as required and therefore, there is a drawback in which firm starting performance of the engine is difficult to be ensured.
Further, according to the motor control apparatus, there is brought about a state in which the starter is driven without being assisted by the electrically-driven motor since the electrically-driven motor is driven as required in starting the engine. Under such a state, the whole load in the cranking operation is borne by the starter and accordingly, there is a drawback of reduced starter durability.
Further, the motor control apparatus carries out a control of driving the electrically-driven motor as required. Accordingly, the control means needs to include a function of determining or selecting assist conditions. This introduces a drawback of complicated control.
Hence, in order to remove the above-described drawbacks, the present invention provides a motor having a drive function and a power generating function directly connected to an engine mounted on a vehicle, a starter for starting connected to the engine, and motor control means for controlling the drive of the motor in cooperation with driving the starter and in accordance with an operating state of the engine when starting the engine.
The motor drive control apparatus according to the present invention can always assist the cranking operation of the starter by driving the motor in starting the engine by controlling the motor in cooperation with driving the starter and in accordance with the operating state of the engine. The motor control means assisting in starting the engine can make the motor bear a portion of load in the cranking operation without making the starter bear the whole load. The motor control means assists the cranking operation by constantly driving the motor in cooperation with driving the starter in starting the engine. Accordingly, there is no need of adding a function of determination, selection, or the like of assist conditions.